Conventionally, in a situation in which a manufactured article, such as an electronic device, is packaged using a packing box, such as a corrugated cardboard case, a typically used method involves providing cushioning between the packing box and the manufactured article (packed article) in order to absorb external impact and vibrations during transportation. The cushioning can be, for example, folded corrugated cardboard or molded pulp cushioning that is recyclable and that is made using waste paper as a material.
Although packing may weaken the impact in a situation in which a packing box tips during transportation or storage of a manufactured article packed therein, or in which the packing box is transported in a sideways state, some of the impact is still transmitted internally. Therefore, the manufactured article inside the packing box may be damaged even if the packing box itself is not damaged. In such a situation, damage to the manufactured article is not confirmed until the packing box is opened. Therefore, it is difficult to determine whether the damage occurred during manufacture of the manufactured article, or whether the damage occurred during transportation or storage of the manufactured article.
PTL 1 discloses impact sensor-equipped cushioning that includes a solution in a supersaturated state, and first and second packing materials that contain the solution. In the aforementioned impact sensor-equipped cushioning, the solution visibly changes state upon receiving external force from an impact, vibrations, etc., enabling visual confirmation that the external force has been received.